From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt1-f172.google.com (mail-qt1-f172.google.com [209.85.160.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4863E2C1AE for ; Fri, 27 Sep 2024 23:21:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727479272; cv=none; b=rGTXo8h14f543pDbrVJZTlpNR21YWZgj2zD2jcuoWyuCddqZGihHv90mf4ubdFxSJVLMRtxR7Ily9mXqKzr0GXkaZde1Q8F8qmP+weA7hio9KP+iTzEMBh6G12adqAVNbcU58G5OuTwlyd1MPQ/Y98hN2S7oA+A3g/B+jqpe0D0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727479272; c=relaxed/simple; bh=FEOA2rJOqDQDdAsoe75gRmLT3XIG7BacAiVDnHTKlsI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=dF0SXhHMtIOJMzRTsQhnhp6G/3M+2F6G28+EXGmd7r6nTopON05ziov6c00nZq2m0zJ+iVqaWH/zi0Oq1spxI5xJA0+4jaG1ArKLofeQ3QXKkUpqRLYD1ZO+8jY8ZDyCYdRfhbevzYhIcKPMQLoj/+2VcitMv5Nepv5ggksBoIg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=XwsFP+mz; arc=none smtp.client-ip=209.85.160.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="XwsFP+mz" Received: by mail-qt1-f172.google.com with SMTP id d75a77b69052e-4582760b79cso13466361cf.2 for ; Fri, 27 Sep 2024 16:21:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1727479270; x=1728084070; darn=lists.linux.dev; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:feedback-id:from:to:cc:subject:date :message-id:reply-to; bh=sRWP0NQhRRIkTJAGGN9No6EkCeFNUseCOmrQOI6Inr4=; b=XwsFP+mzO+7ZRKlBB0ibxEa4KnB8Mf2nIBM/lTPsPX1qCvhnPHMfOKwivwZukUR6pe iQObTbtY+GDW57+H4Syp0btaiIhQDDK74hU61u5hsW9MmRP1UdopFHR4zPtiWzzS6e8l dYsz19wYJ0kaADGNvFVvaef4RHHK4p2jYuUwlOfoEW5Ev9G1iy4a8cweF4vqTBvIhmST bt0ytvVToCjq9bGZ0NATqwFgfFiU0OAA6XHy0Z5fs0L/fct0w3KA+pLFmNaUnPxh4Pyq +9fM3gaAQcGmRWd48fvdZimv/CLEwij/5OrA9PaHGeIv/PvIW8Zo1rixlF47jjVE7VgZ T/fA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727479270; x=1728084070; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:feedback-id:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=sRWP0NQhRRIkTJAGGN9No6EkCeFNUseCOmrQOI6Inr4=; b=TeQEE0H7luMuS2hi2Ym/9B5eCu5kcNDepI5Z8QdcdgTGU7T9lrw5fk8no5+b89AJc4 Qm3yLU69RFs1f66ZAKZsx3WIknkxY7h9jLXnR+iKmQg6tg4o3Ko6tM/BRBUjDygcAPfB 74N/0pN0vGAJ2WwbmHstRlAW7oF68RM99d5LuMB8rwv/XGLFIVMDqIb03ZEnTEotscDf BidCPSqy1sC7DZCGWtaYXO3DG80rx/aRVEctG3LgGqZZc95Punjy0SAmZajDvXERLGzX 8xLIOfpOrsZN9y5n8GpRLULVq7VfoydPaFzwrTjcUE7yudMGW7n1gkU7PPSZQ9AF69hf oYhQ== X-Forwarded-Encrypted: i=1; AJvYcCXg2vqOkMW8+Gbou8T2GXH4RshYeJhhDt/9WkQNfu9RJ9Pl46vmYUcMoU8+aXa4+/htN+p7@lists.linux.dev X-Gm-Message-State: AOJu0Yxz7wi3BAgHYGaniEYe2eGsMHrU+fCotvk2Pp6Vqr45bjBC0E0S s6I2eIWeh8n+sW6J2hdyMhVHfnJ1VqM5aeqKRWkU+YzfleQ2keVA X-Google-Smtp-Source: AGHT+IFVYWr7YfLP2ZOmoXZeV+ICDbqgORNSo+RKjNe6YotBXK+vAKKnLzTlsohS5VqeARSVg8gozA== X-Received: by 2002:ac8:5a49:0:b0:458:5191:65c1 with SMTP id d75a77b69052e-45c9f20e2e4mr63920411cf.26.1727479270057; Fri, 27 Sep 2024 16:21:10 -0700 (PDT) Received: from fauth-a2-smtp.messagingengine.com (fauth-a2-smtp.messagingengine.com. [103.168.172.201]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-45c9f290162sm12661021cf.3.2024.09.27.16.21.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 27 Sep 2024 16:21:09 -0700 (PDT) Received: from phl-compute-01.internal (phl-compute-01.phl.internal [10.202.2.41]) by mailfauth.phl.internal (Postfix) with ESMTP id E1EA01200043; Fri, 27 Sep 2024 19:21:08 -0400 (EDT) Received: from phl-mailfrontend-01 ([10.202.2.162]) by phl-compute-01.internal (MEProxy); Fri, 27 Sep 2024 19:21:08 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeeftddrvddutddgvddvucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdggtfgfnhhsuhgsshgtrhhisggvpdfu rfetoffkrfgpnffqhgenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnh htshculddquddttddmnecujfgurhepfffhvfevuffkfhggtggujgesthdtredttddtvden ucfhrhhomhepuehoqhhunhcuhfgvnhhguceosghoqhhunhdrfhgvnhhgsehgmhgrihhlrd gtohhmqeenucggtffrrghtthgvrhhnpedttddugeeuveeghffgueffteffueehkeegtdff feehhfejfffhgfefgeegteeghfenucffohhmrghinhepvghffhhitghiohhsrdgtohhmne cuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepsghoqhhu nhdomhgvshhmthhprghuthhhphgvrhhsohhnrghlihhthidqieelvdeghedtieegqdduje ejkeehheehvddqsghoqhhunhdrfhgvnhhgpeepghhmrghilhdrtghomhesfhhigihmvgdr nhgrmhgvpdhnsggprhgtphhtthhopedvledpmhhouggvpehsmhhtphhouhhtpdhrtghpth htohepmhgrthhhihgvuhdruggvshhnohihvghrshesvghffhhitghiohhsrdgtohhmpdhr tghpthhtohepthhorhhvrghlughssehlihhnuhigqdhfohhunhgurghtihhonhdrohhrgh dprhgtphhtthhopehlihhnuhigqdhkvghrnhgvlhesvhhgvghrrdhkvghrnhgvlhdrohhr ghdprhgtphhtthhopehgrhgvghhkhheslhhinhhugihfohhunhgurghtihhonhdrohhrgh dprhgtphhtthhopegsihhgvggrshihsehlihhnuhhtrhhonhhigidruggvpdhrtghpthht ohepphgruhhlmhgtkheskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepfihilhhlsehkvg hrnhgvlhdrohhrghdprhgtphhtthhopehpvghtvghriiesihhnfhhrrgguvggrugdrohhr ghdprhgtphhtthhopehsthgvrhhnsehrohiflhgrnhgurdhhrghrvhgrrhgurdgvughu X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 27 Sep 2024 19:21:08 -0400 (EDT) Date: Fri, 27 Sep 2024 16:20:18 -0700 From: Boqun Feng To: Mathieu Desnoyers Cc: Linus Torvalds , linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Sebastian Andrzej Siewior , "Paul E. McKenney" , Will Deacon , Peter Zijlstra , Alan Stern , John Stultz , Neeraj Upadhyay , Frederic Weisbecker , Joel Fernandes , Josh Triplett , Uladzislau Rezki , Steven Rostedt , Lai Jiangshan , Zqiang , Ingo Molnar , Waiman Long , Mark Rutland , Thomas Gleixner , Vlastimil Babka , maged.michael@gmail.com, Mateusz Guzik , rcu@vger.kernel.org, linux-mm@kvack.org, lkmm@lists.linux.dev Subject: Re: [RFC PATCH] compiler.h: Introduce ptr_eq() to preserve address dependency Message-ID: References: <20240927203334.976821-1-mathieu.desnoyers@efficios.com> <23882bd6-c0e0-4f6c-9000-b79216194198@efficios.com> Precedence: bulk X-Mailing-List: lkmm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <23882bd6-c0e0-4f6c-9000-b79216194198@efficios.com> On Fri, Sep 27, 2024 at 07:05:53PM -0400, Mathieu Desnoyers wrote: > On 2024-09-27 22:33, Mathieu Desnoyers wrote: > [...] > > > --- > > include/linux/compiler.h | 62 ++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 62 insertions(+) > > > > I'm wondering if this really belongs in compiler.h, or if it's so > RCU/HP specific that it should be implemented in rcupdate.h ? > > [... ] > > +static __always_inline > > +int ptr_eq(const volatile void *a, const volatile void *b) > > And perhaps rename this to rcu_ptr_eq() ? > I think the current place and name is fine, yes RCU is the most important address dependency user, but there are other users as well. Regards, Boqun > Thanks, > > Mathieu > > > +{ > > + OPTIMIZER_HIDE_VAR(a); > > + OPTIMIZER_HIDE_VAR(b); > > + return a == b; > > +} > > + > > > > -- > Mathieu Desnoyers > EfficiOS Inc. > https://www.efficios.com >